A medical examiner’s report released Tuesday determined that infamous hoax writer Paul Horner’s death in September was due to mixing several drugs, including the synthetic opioid fentanyl.

Horner was found dead in bed Sept. 18 in the Laveen area of southwest Phoenix. He was 38.

The report called the death accidental.

The Maricopa County Medical Examiner's office autopsy and toxicology results reveal that Horner had a mixture of clonazepam, despropionyl fentanyl, diazepam, ethanol and furanyl fentanyl in his system.

"Despropionyl fentanyl … is a synthetic opioid and is a known chemical intermediary used in clandestine manufacture of illicit fentanyl," the report stated.

In its various forms, fentanyl is 50 to 100 times more potent than morphine, according to the U.S. Centers for Disease Control and Prevention.

Five times more people died of overdoses involving synthetic opioids in 2016 than in 2013, a sharp increase that is mostly attributed to the rise of illicitly-manufactured fentanyl, according to an October report from the CDC.

History of drug use

The U.S. Drug Enforcement Administration in Phoenix has determined 32 Maricopa County residents died of Fentanyl overdoses in the past 18 months.(Photo: U.S. Drug Enforcement Administration)

Horner had a years-long history with drugs.

He was arrested in Chandler in 2011 and found to be in possession of more than $15,000 worth of drugs, including 247 grams of ketamine, heroin, diazepam, oxycodone, Prozac and paraphernalia, including hundreds of syringes.

He was under the influence of ketamine at the time of his arrest, police said.

In a police report, investigators said Horner bought and sold drugs online from India, "appeared to be coming down from an opiate-based high" and suspected he may be an addict. He served four months in jail.

Legacy of hoaxes, false stories and satire

For at least the past six years, Horner published a stream of intentionally false stories designed to inflame readers and go viral.

Using official-sounding domain names like CNN.co.de, Horner’s stories swerved from over-the-top jokes to political firebombs. Among them was the super-viral "Donald Trump Protester Speaks Out: 'I Was Paid $3,500 To Protest Trump's Rally."

Many of his hoaxes were picked up by news outlets and political players who failed to fact-check the claims.

That influence led the Washington Post to credit Horner with having an "enormous impact" on the 2016 presidential election.

"I think Trump is in the White House because of me," Horner told the Post in November 2016.

After the election, Horner gained recognition as the Internet's most prolific hoaxer. He appeared on CNN's "Anderson Cooper 360" and spoke before the European Parliament.

Since his death, "at least 20 fake news websites registered in Horner’s name have gone offline," according to Poynter.